DNA – Repair Protein Key to Converting Carbs to Fat?

Dr. Hei Sook Sul

Dr. Hei Sook Sul

Yesterday, I had the pleasure of listening to Hei Sook Sul (picture) from the University of California, Berkeley, who spoke at the Alberta Diabetes Institute here in Edmonton (host Dennis Vance).

Sul’s group, which works on better understanding the molecular mechanisms underlying the synthesis of fatty acids, recently identified DNA-PK, a protein kinase that plays a role in DNA repair, as a possible key factor in the activation of fatty acid synthase (FAS), the enzyme that helps convert dietary carbohydrates to fat.

In a paper, recently published in the journal Cell, Sul’s group showed that feeding high-carb diets to mice with a disabled DNA-PK gene resulted in lower levels of body fat than in their normal counterparts. This was evidently due to their inability to convert carbs to fats, a key step when excess calories from carbs need to be stored for future use.

As always, one must be careful in jumping from findings in mice to humans, and although DNA-PK may well seem an attractive pharmacological target to prevent fat accumulation in people who eat high-carb diets, it is important not to forget that this enzyme also plays an important role in DNA repair, a possible critical factor in preventing cells from mutating into cancer cells.

Nevertheless, the elucidation of this important metabolic step – the conversion of dietary carbs to fat – is certainly a major breakthrough in our understanding of how the body metabolizes carbohydrates and definitely provides fascinating new insights into the complex workings of nutritional biology.

Edmonton, Alberta